Collapsible tap



UNITED m (PATENT OFFICE.

. vrcron a. mantra or WAYInnsBono, PENNSYLVANIA, AssIeNon TO THE VICTOR TOOL COMPANY, or, WAYNESBORO, PENNSYLVANIA, A CORPORATION or PENN- SYLVAN IA.

Specification of Letters Patent.

, coLLAPsIBLE TAP.

Patented Oct. 26, 1920.

Application filed December 31,1919. Serial No. 348,569.

To dZZwZwmitmaj concern. j

Be it known that I, VIoron R. Kooln'rz, a citizen of the United States, residing at Waynesboro', in the county of Franklin and State of Pennsylvania, have inventedcer'tain new and useful Improvements in Collapsible Taps, of which the following is a specification.

In die tap headsof the collapsible type having overhanging or projecting cutting elements or chasers that are used for tapping close to a shoulder or to the botom of a blind hole, difficulty has been experienced in holding the cutting elements or chasers rigidly. They are apt to be forced inwardly or tilted slightly by the pressure against the work, resulting in an undesirable taper in the threads. This is particularly true on taps of the smaller diameters, inasmuch as the cutting element or chaser is very short radially.

The object of the present invention is to provide a structure of this type in which the cutting elements are very effectively held, having a bearing support throughout their width, and directly adjacent to the cutting elements.

In the accompanying drawings,

Figure 1 is a longitudinal sectional View through a collapsible tap, and showing the improved cuttingstructure in place therein.

Fig. 2 is an end elevation of the same.

Fig. 3 is an end elevation of the cap.

Fig. i is a sectional view through the cap.

Fig. 5 is an inside face view.

Fig. 6 is a detail sectional view snbstantially on the line 6-6 of F ig. 1.

Fig. 7 is a detail perspective View of one of the dies. I

The die tap head in the embodiment disclosed consists of relatively movable members 8 and 9, the latter being slidable longitudinally in a bore 10 of the former, and having a tapered outer end 11. This tapered end is provided with a plurality of inclined guideways 12 having ribs 13 on their side walls. T he outer member 8 is provided with slots 14 alined with the guideways 12. I

Chasers are mounted in said guideways 12 and slots 14. Each chaser consists of a body portion 15 having an inclined inner edge 16 that is slidable in the guideway 12 and is provided in one side with a groove 17 that receives the rib 13. From the outer end of the body projects an integral portion 18, constit'nting thecutting element. This portion 18' is of less width than the body and of less thickness than the same, forming a trans verse shoulder 19 at the juncture of the body and said portion. The portion 18, as clearly shown in Fig. 1, projects beyond the head and the chasers are held in place by a cap 20 extending over the outer ends of the body, and having radial slots 21through which the projecting portions 18 extend. The cap is held in place by screws 22 or other suitable fasteners. It will be noted particularly by reference to Figs. 2 and 6 that the slots 21 are just wide enough to permit the portions 18 to pass therethrough so that the shoulders 19 bear against the inner side of the cap, and in fact this bearing extends the entire width of each chaser.

As a consequence, the chasers have supporting bearings throughout their entire width and directly at the juncture of the bodies 15 with the projecting portions 18. It has been found that this effectively secures the chasers against any lateral or tilting movement due to the pressure of the work against the outer corners or cutting threads of the dies, thereby insuring accurate work and obviating the article being provided with a tapered thread.

From the foregoing, it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art without further description, and it will be understood that various changes in the size, shape, proportion and minor details of construction may be resorted to without departing from the spirit or sacrificing any of the advantages of the invention.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent, is I 1. In a tool of the character set forth, the

combination with a support, of a tap mounted thereon and having a projecting portion provided with a cutting element, said chaser having a shoulder disposed alongside the projecting portion, and means on the support against which the shoulder bears, to maintain the chaser against displacement.

2. In a tool of the character set forth, the combination with a supporting head, of a tap comprisingabody mounted on the head and having a portion projecting from the head and provided with cutting means, said projecting portion being of less thickness than the body, forming a transverse shoulder, and

means on the support against which the 5 shoulder bears to maintain the chaser against displacement.

8. In a tool of the character set forth, the combination with a supporting head, of a die comprising a body mounted 011 the head and having a portion projecting from the head and provided with cutting means, said projecting portion being of less width and thickness than the body, forming a transverse shoulder at the juncture of said body and portion, and a cap carried by the head and having an opening through which the said portion projects, the said shoulder bearing against said cap alongside the opening. a

4. In a tool of the character set forth, the

combination with a supporting head comwith the inclined portion of the other memher, said chaser having a cutting portion that projects through the slot of the cap and is of less thickness than the body, forming a transverse shoulder that slidably bears against the inner side of the cap alongside the slot.

In testimony whereof, I aflix my signature in the presence of two Witnesses.

VICTOR R. KOONTZ.

Witnesses: I i

W. R. DAVISON, PEARL RIDENOUR. 

